Railway signaling system



I Sept. 1, 1942. E, M, ALLEN 2,294,438.

RAILWAY SIGNALING SYSTEM Filed Nov. 25, 1941 2 Sheets-Sheet l INVENTOH P 1942. E. M. ALLEN RAILWAY SIGNALING SYSTEM 2 Sheets-Sheet 2 Filed Nov 25, 1941 E? v 1? W !I.1|\ M M q x Z 5 6 5 m H 1 awf 5 1% it 0 H w w; W w w W: WW. m w -mlfl mww z e Z w :i! mfi. w M,

[NV NYOH Ea M. A Z Z011 BY H15 ATTOR EY Patented Sept. 1, 1942 UNITED STATS A'EENT ()FFICE RAILWAY SIGNALING SYSTEM Application November 25, 1941, Serial No. 420,371

Claims.

My invention relates to railway signaling apparatus and particularly to improved means for preventing improper operation of certain types of equipment in the event energy is improperly supplied to some of the circuits employed in the system.

It is customary at interlockings to provide means to look a track switch against movement under certain conditions when a signal governing movement of traffic over the switch is manually put to stop. The purpose of such locking is to prevent movement of the switch when a train is approaching at such speed that it cannot be readily stopped without overrunning the switch.

To insure proper functioning of switch locking means of this kind it is essential that the stop indication of the home signal be accurately checked. Where searchlight signals of the type shown in United States Patent Reissue No. 14,940 to Eli J. Blake are employed it is customary to provide a red repeater relay the circuit of which is controlled by contacts of the signal mechanism so that the relay is energized when and only when the signal is displaying its red or stop indication, and is deenergized when the signal is displaying either its yellow or its green indications.

Because of the limited contact capacity of sig nals of this type one terminal of the winding of the signal so that the relay is energized only I when the signal displays its red or stop indication. Under normal conditions this provides a satisfactory indication of the aspect displayed by the signal. However, if the wiring is defective and connection is improperly made to the wire controlled by the signal mechanism, the red repeater relay will be energized even though the signal is displaying either its green or its yellow aspects.

It is an object of this invention to provide means adapted for use in a system of the type described to prevent movement of a track switch in the event that the red repeater relay is improperly energized.

Another object of the invention is to provide means adapted for use in the signaling systems at interlockings to prevent clearing of the signals if energy is improperly supplied to portions of the signal control circuits.

Other objects of the invention and features of novelty will be apparent from the following description taken in connection with the accompanying drawings.

I shall describe one form of signaling system embodying my invention and shall then point out the novel features thereof in claims.

In the drawings Figs. 1A and 1B when placed together with Fig. 1B at the right of Fig. 1A form a diagram of a system embodying my invention:

Referring to the drawings, there is shown therein a stretch of railroad track having a main track A, and a siding or branch track P which is connected with the main track A by a track switch W. The the normal and reverse positions by a power operated switch machine SM which may be of any well known construction, and which is controlled by a polarized switch control relay WR.

The main track A has track rails I and 2 which are divided by insulated joints 3 into the usual track sections which are here designated 3T, 2T, IT and 8T. The track sections ST and 2T together constitute an approach zone or approach stretch, while the detector section IT includes the switch W and the adjacent portions of the tracks A and P.

Each of the track sections is provided with track circuit apparatus which may be of any well known type. As shown each section has a track battery connected across the rails of the section at one end of the section, and a track relay TR connected across the rails of the section at the other end of the section.

The track stretch is provided with appropriate signals for governing movement of trafiic across the switch on the main track and between the main track and the branch or side track. As shown these signals are of the searchlight type.

The signals governing movement of trains from left to right include a home signal 2R which includes an upper portion ZRA which controls movement of traffic through the main track A across the switch W, and a lower portion 2R0 which controls movement of trafic from the main track A across the switch W to the siding or branch track P. The main track also has a distant signal 2D which is located at the entrance to section 2T. The signals governing movement of trafiic from right to left include a signal 2L which has an upper portion 2LA which governs normal movement of traific on the main track A across the switch W, and a lower or callon portion 2LC. In addition, there is a signal 2LD which governs movement of traffic from the rack switch W is moved between branch track P across the switch W to the main track A.

The signals 'ZLA, ERA and ED are each capable of displaying a red or stop indication, a yellow or caution indication, and a green or clear indication. The signals ELC, 2L1) and 2R0 are each capable of displaying only a red or stop indication, and a yellow or caution indication.

Each signal includes a three-position circuit controller, While the mechanism i arranged so that when the winding of the signal mechanism is energized by current of one relative polarity, front contact G and back contact Y of its circuit controller are closed, and the signal displays a green light indicating clear or proceed; when the winding is energized by current of the opposite polarity, front contact Y and back contact G of the circuit controller are closed and the signal displays a yellow light; and when the winding is deenergized, both back contacts are closed and the signal displays a red light.

In most instances the contacts associated with a relay are shown directly under the relay winding, but in some cases, in order to simplify the drawings, relay contacts are shown separate from the relay winding, and where this is done the relay with which the contacts are associated is identified by appropriate reference characters located above the contacts.

The circuits and apparatus relating to the control of trafiic moving from left to rig t have been shown in substantially complete form, while, in order to simplify the disclosure, portions of the equipment relating to the control of traific moving from right to left has been omitted. This equipment is similar to that for movement oi traffic from left to right.

The signals 2L and ER at the track switch are controlled by a signal control lever K and by a switch indication relay WPR, while the supply of energy to the switch control relay WR is controlled by a switch control lever J. The circuit of the switch control relay WR is controlled by the track relay ITR of the detector section, and by contacts of the approach locking relays RASR and LASR.

The signal control lever K and the switch control lever J may be located at any convenient point, as in an interlocking tower, and these levers may form a part of an interlocking rnachine. While the polarity of the energy supplied to the circuits of the switch and signal control relays is illustrated as being controlled by lever operated contacts, it is contemplated that the polarity of the energy supplied to these ciro cuits may be controlled by relay contacts or other appropriate means.

The equipment is shown in the condition which it assumes when the track stretch is vacant, the switch W is in its normal position, and the signal control lever K is in its intermediate position so that the signals ER and EL at the switch W are at stop.

As the signal control lever K is in its intermediate position, the contacts it and ii controlled thereby interrupt the supply of energy to the signal control relay GR and the neutral contacts of this relay are released while the polar contacts of the relay remain in their last operated position. They are shown in their left-hand positions in which they permit clearing of the signals governing movement of traflic from the right to the left.

As the neutral contacts i2 and E3 of relay GR are released and its polar contacts 22 and 23 are in their left-hand positions, the circuit of the operating winding of the signal ZRA is interrupted so that this signal is conditioned to provide its red or stop indication. Likewise, contacts I3 and M of relay GR interrupt the circuit of the winding of signal 2LA and this signal provides its red or stop indication.

As the switch W is in its normal position switch operated contacts [5 and I6 establish circuits to supply energy of normal polarity from a source of direct current, the terminals of which are designated B and C, to the switch indication relay WPR so that the neutral contacts of this relay are picked up and the polar contacts of the relay occupy their normal or left-hand positions as shown.

As polar contacts l8 and ii) of relay WPR are in their left-hand positions, the circuit of the winding of signal RC is interrupted and this signal shows stop. Likewise, as the contacts 20 and 21 of relay WPR are in their left-hand positions, the circuit of the winding of signal ZLD is interrupted and this signal shows stop. At this time the call-on relay COR is assumed to be deenergized and its contacts 23 and 24 prevent the supply of energy to the winding of signal 2LC, while its contacts 26 and 27 interrupt a circuit for supplying energy to the winding of signal 2R0 so that signals ZRC and 2LC display stop indications.

As the signal ZRA is displaying its red indication, its front contacts G and Y are both open and energy is not supplied to the winding of relay RAHD and the contacts of this relay are released with the result that energy of reverse polarity is supplied to the winding of signal 2D and this signal displays its yellow or caution indication while its back contact G is closed. At this time back contacts G and Y of signal ZRA are both closed and energy is supplied to the relay RAR so that the contacts of this relay are picked up. As signal 2R0 is at stop, its back contacts G and Y are both closed and ener y is supplied to the winding of relay RR over the circuit which is traced from terminal B through back contact G of signal 2D, back contacts G and Y of signal 2R0, front contact 3%! of relay RAR, and winding of relay RR to terminal C so that the contacts of this relay are picked up.

As sections 3T and 2T are both unoccupied, the track relays for these sections are picked up and energy is supplied to the approach relay RAP over the circuit which includes front contact 3! of track relay STR and front contact 32 of track relay 2TB. Accordingly, the contacts of relay RAP are picked up, and the pick-up circuit for the approach locking stick relay RASR is complete and is traced from terminal B through back contact 33 or' left-hand polar contact 34 of signal control relay GR, back contact 36 of relay RAI-ID, front contact 38 of relay RR, front contact 49 of relay RAP, back contact 8| of relay RTER, and winding of relay RASR to terminal C. The contacts of relay RASR are picked up and its contact l! establishes a stick circuit to maintain the relay winding energized after release of contact Ail. In addition, contacts 43 and i of relay RASR are picked up to permit energy to be supplied to the winding of the switch control relay WR. The circuit of this relay also includes contacts 45 and 4'! of relay ITR which are closed as section IT is vacant. The circuit of relay WR is also controlled by the approach locking relay LASR, while this relay is governed in a manner similar to relay RASR so as to prevent movement of the switch when trains are approaching from the right. As the circuit of the switch control relay WR is complete, the operator, by moving the switch control lever J, may change the polarity of the energy supplied to the switch control relay WR and thereby cause this relay to condition the switch machine SM to move the switch The relay GDR is provided to check the integrity of the circuits by which the signal control relay GR controls the signals associated with the switch W. As hereinafter explained, this relay is normally deenergized, but in the event that energy is improperly supplied to the signal circuits this relay will be energized. These circuits are assumed to be in proper order and accordingly the contacts of relay GDR are released and its contacts and 48 are closed to permit energy to be supplied to the winding of relay GR.

If the operator wishes to clear the signals governing movement of trafiic from left to right, he may do so by moving the lever K to its position R. In this position of the lever K its contacts Ill and H establish circuits to supply to the relay GR energy of the polarity effective to cause the polar contacts of the relay to move to their righthand positions. Accordingly, on this movement of the lever K thepolar contacts of the relay GR move to their right-hand positions while the neutral contacts of the relay pick up so that contacts 33 and 34 of the relay interrupt the supply of energy to the relay RASR and the contacts of this relay release.

Release of contact M of relay RASR interrupts the stick circuit for the relay, while release of contact 49 interrupts the circuit of relay GDR to maintain this relay released, and release of contact 50 establishes the circuit to supply energy to the winding of the signal 2RA. This circuit is traced from terminal B of a source through back contact 50 of relay RASR, front contact 52 of relay LASR, right-hand polar contact 53 and front neutral contact I 4 of relay GR, back contact 54 of the time element stick relay LETSR, not shown, associated with relay LASR, back contact 55 of relay RETSR, front contact 56 of relay WPR, front neutral contact I2 and right-hand polar contact 58 of relay GR, left-hand polar contact l8 of relay WPR, front contact 59 of relay STR, and front contact 60 of relay ITR to one terminal of the winding of signal 2RA, through this winding, front contact 6| of relay ITR, front contact 62 of relay BTR, left-hand polar contact IQ of relay WPR, right-hand polar contact 64 and front neutral contact I3 of relay GR, and I front neutral contact 65 of relay WPR to terminal C of the source. Accordingly, the winding of signal 2RA is energized and this signal is conditioned to provide a proceed indication.

The circuit of the winding of the signal 2RA may include means, not shown, for controlling the polarity of the energy supplied to the winding of the relay in accordance with the aspect displayed by the adjacent signal in advance so that signal 2RA will provide its yellow indication when the adjacent signal in advance is at stop, and will display its green indication when the adjacent signal in advance is at caution or clear. The means by which the polarity of the energy supplied to the signal 2RA is controlled is not a part of this invention and any means well known in the art may be employed for this purpose. Furthermore, the system of this invention is not aifected by the proceed indication that is displayed by the signal 2RA, and in order to simplify the disclosure the means for controlling the polarity ofthe energy supplied to the signal 2RA has been omitted.

As signal 2RA is displaying a proceed indication, either its Y or G front contact is closed while the corresponding back contact is open. Energy, therefore, is supplied to the relay RAHD over the circuit which includes a front contact of signal 2RA, while the circuit of relay RAR is interrupted at a back contact of signal 2RA. When contacts 68 and 69 of relay RAHD are released, energy of the polarity effective to cause signal 2D to provide its yellow indication is supplied to the winding of this signal. On picking up of the contacts of relay RAl-ID energy of the polarity opposite to that previously supplied is supplied to the winding of signal 2D and this signal operates to provide its green indication while its back contact G is opened to interrupt th circuit of relay RR. The circuit of the relay RR is also interrupted at this time by contact 30 of relay RAR which is released when signal 2RA displays a proceed indication.

At this time, therefore, as relay RAHD is picked up, its contact 35 interrupts the circuit of the locking relay RASR, while as relay RR is released, its contact 38 additionally interrupts the circuit of relay RASR. Accordingly, the contacts of relay RASR are released and interrupt the circuit of the switch control relay WR to prevent movement of the switch as long as signal 2RA displays a proceed indication and signal 2D displays its clear indication.

If a train moving from left to right now enters the approach stretch, track relay 3TR will release and its contact 3| will interrupt the circuit of the approach relay RAP so that its contact 40 interrupts the circuit of relay RASR to prevent energization of relay RASR until expiration of the time delay period determined by the time element device RTER if the signals are placed at stop while the approach stretch is occupied.

The time release of the approach locking operates in the usual manner well known in the art and its operation will not be traced in detail.

As pointed out above when the lever K is operated to clear the signal 2RA and this signal operates to provide a proceed indication, the circuit of the relay RAR is interrupted at one of the back contacts of the signal 2RA, and the contacts of the relay RAB should release so that its contact 3% interrupts the circuit of the relay RR to cause release of its contact 38 to interrupt the circuit of the locking relay RASR and thereby prevent movement of the switch.

However, if the circuit of the relay RAR is defective so that when the signal 2RA displays a proceed indication, energy continues to be supplied to the relay RAR so that its contacts 1 emain picked up, or if the relay contacts remain picked up for any other reason, contact 313 of relay RAR will be closed to permit energy to be supplied to the relay RR.

The circuits heretofore employed have been arranged so that when the contacts of the relay RR are picked up, its contact 33 establishes the circuit of the locking relay RASR so that energy may be supplied to this relay to pick up i s contacts and thus permitenergy to be supplied to the switch control relay WR and thereby permit the switch to be moved.

Undersome conditions the other means governing the circuit of the relay RR and the circuit of the lock relay RASR may not be effective so that the contact 38 of relay RR will be closed and the circuit of the relay RASR may be established even though the signal ERA is displaying a proceed indication.

The system of this invention eliminates this possibility and insures that the circuit of the switch control relay cannot be established when the signal ZRA is displaying a proceed indication.

For purposes of illustration it will be assumed that a train passes through the track stretch and that when the train enters the detector secion IT and the contacts 66 and 6| of the track relay ITR release and interrupt the circuit of the winding of the signal ERA, the signal continues to display a proceed indication, either because of a defect in the signal mechanism or in the circuit of the signal. It will be assumed also that there is a defect in the circuit of the relay BAR, or in the relay itself, so that its contacts remain picked up even though the signal ERA is displaying a proceed indication.

As the signal ERA is assumed to be displaying a proceed indication, energy is supplied to the relay RAHD, while as the contacts of the relay RAB are picked up, its contact 32 is closed to permit energy to be supplied to the relay RR. At this time it will be assumed that a portion of the train remains in section 2T so that contacts 35 and E6 of relay 2TB are released and prevent the supply of energy to the signal 2D. Accordingly, the signal 2D will display its stop indication and its back contact G will be closed so that energy is supplied to the relay RR and its contact 38 will be closed to permit energy to be supplied to the relay RASR.

As section IT is occupied, track relay ITR is released, and, except for contact 36 of relay RAHD which has been added by this invention, would establish a pick-up circuit for the locking relay RASR. This circuit includes back contact 1.! of relay lTR, back contact 19 of call-on relay COR, front contact 33 of relay RR, back contact 88 of relay ETR, back contact 8! of relay RTER, and the winding of relay RASR.

Under th conditions outlined, therefore, energy may be supplied to the relay RASR and its contact M will establish a stick circuit to maintain the relay energized after the train vacates the detector section VI and the contacts of relay ITR. pick up.

When the train advances into section 8T, track relay 8TB, releases and its contact 82 establishes a circuit shunting the contact T! of track relay ITR so that energy will continue to be supplied to the relay RASR after the train vacates section iT and contact ll of track relay ITR is picked up. Accordingly, as long as the train remains in section 8T, energy may be supplied to the relay 'RASR over the circuit which includes back contact 82 of track relay STR. and its own front contact M. If before the train vacates section 8T the operator restores the signal lever K to its intermediate position, contact 33 of relay GR will be released and establish a circuit to maintain the supply of energy to the relay RASR after the train vacates section 8T.

If the train under consideration vacates section 2T before another train enters the section, contacts 75 and 16 of track relay ZTR will pick up and establish the circuit of signal 2D. At this time, as signal ERA is assumed to be displaying a proceed indication, the energy supplied to the signal 2D will be of the polarity effective to cause the signal 2D to display its green indication and its back contact G will be open and will interrupt the circuit of relay RR so that contact 38 of this relay releases and interrupts the circuit of the relay RASR to thereby cause release of the contacts of relay RASR and resultant locking of the switch.

However, if before the train under consideration vacates section 2T a second or following train enters the section, the track relay of the section will remain released when the first train vacates the section. Accordingly, the signal 2D will remain at stop and will maintain the circuit of the relay RR so that contact 38 of relay RR maintains the circuit of the relay RASR. As a result, when the first train vacates the detector section IT, the lock relay RASR is maintained energized by current supplied over back contact 82 of relay 8TB or back contact 33 of relay GR, and the circuit of the switch control relay WR will be complete so that the operator may move the switch even though the signal ZRA is improperly displaying a proceed indication, and even though a train is in section 2T and is approaching the switch. Obviously this is an undesirable situation as the switch may be in transit when the train enters the detector section and renders the detector looking effective with the result that the switch will be stopped in mid stroke.

The system provided by this invention is ar ranged to eliminate the possibility that the switch will be improperly unlocked under the conditions outlined.

In the system of this invention back contact 36 of relay RAHD is included in the circuit of the locking relay RASR so that if the signal LRA continues to display a proceed indication after the supply of energy to the winding of the signal is interrupted, the relay RAHD-will remain energized and its contact 36 will prevent the supply of energy to the relay RASR even if the relay RAR. is improperly energized so that the relay RE is picked up.

It will be seen, therefore, that the system provided by this invention operates to insure that the switch will be locked when the signal ZRA displays a proceed indication, and that this looking will be effective even if the relay RAR is improperly energized.

The system of this invention is also arranged so that the integrity of the circuits controlled by the relay GR. for governing the signals is checked to prevent clearing of a signal if energy is improperly supplied to'these circuits.

As shown in the drawings, the relay GDR is provided and has one terminal of its winding connected to the grounded or common terminal C of the source, while the other terminal of its winding is connected through front contacts of the locking relays RASR and LASR to the network over which energy is supplied to the signals 2B. and 2L which are governed by the relay GR.

Accordingly, when the lock relays are energized to permit movement of the switch, the relay GDR is connected to the signal network. If the circuits of this network are all in proper form, they will not be energized at this time and the relay GDR will be deenergized and its contacts t5 and as are released to permit energy to be supplied to the signal control relay GR so that this relay may be energized to clear the appropriate one of the signals. As soon as the signal control lever K is operated to supply energy to the relay GR and the neutral contacts of this relay pick up, one or the other of the locking relays RASR and LASR releases and interrupts the circuit of the relay GDR, to

prevent energization of this relay by current supplied to the signals.

If, on the other hand, energy is supplied to the signal network at a time when the locking relays RASR, and LASR are both picked up, the relay GDR will be energized and its contacts 45 and 43 will interrupt the circuit of the relay GR to thereby prevent energization of this relay and thus prevent clearing of any of the signals controlled by this relay. Accordingly, the signals will be held at stop and the inability of the operator to clear the signals will inform him of the defective condition of the signal network.

Although I have herein illustrated and described only one form of improved signaling system embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a stretch of railway track containing a track switch movable between a normal and a reverse position, an approach looking relay effective when deenergized to prevent movement of the switch and effective when energized to permit the switch to be moved, a Searchlight signal governing movement of traffic across the switch, said signal being capable of displaying a stop indication and at least one proceed indication, a first and a second auxiliary relay associated with said signal, means effective when the signal displays its stop indication for supplying energy to the first auxiliary relay, means effective when the signal displays a proceed indication for supplying energy to the second auxiliary relay, and a circuit for supplying energy to said approach locking relay, said circuit including a front contact of said first auxiliary relay and a back contact of said second auxiliary relay.

2. In combination, a stretch of railway track containing a track switch movable between a normal and a reverse position, an approach locking relay effective when deenergized to prevent movement of the switch and effective when energized to permit the switch to be moved, a searchlight signal governing movement of traffic across the switch, said signal being capable of displaying a stop indication and at least one proceed indication, a first and a second auxiliary relay associated with said signal, means effective when the signal displays its stop indication for supplying energy to the first auxiliary relay, means effective when the signal displays a proceed indication for supplying energy to the second auxiliary relay, a signal control relay governing said signal so that the signal can only be conditioned to provide a proceed indication when said signal control relay is energized, and a circuit for supplying energy to said approach locking relay, said circuit including back contacts of the signal control relay and of the second auxiliary relay and a front contact of said first auxiliary relay.

3. In combination, a section of railway track containing a track switch movable between a normal and a reverse position, an approach locking relay effective when deenergized to prevent movement of the switch and effective when energized to permit the switch to be moved, a Searchlight signal governing movement of traflic across the switch, said signal being capable of displaying a stop indication and at least one proceed indication, a first and a second auxiliary relay associated with said signal, means effective when the signal displays its stop indication for supplying energy to the first auxiliary relay, means effective when the signal displays a proceed indication for supplying energy to the second auxiliary relay, a track relay for said track section which is released when said section is occupied, a pick-up circuit for said approach locking relay including a back contact of said track relay, and a stick circuit for said approach locking relay including its own front contact, said pick-up and stick circuits each including a front contact of said first auxiliary relay and a back contact of said second auxiliary relay.

4. In combination, a section of railway track containing a track switch movable between a normal and a reverse position, an approach looking relay effective when deenergized to prevent movement of the switch and effective when energized to permit the switch to be moved, a Searchlight signal governing movement of traffic across the switch, said signal being capable of displaying a stop indication and at least one proceed indication, a first and a second auxil iary relay associated with said signal, means effective when the signal displays its stop indication for supplying energy to the first auxiliary relay, means effective when the signal displays a proceed indication for supplying energy to the second auxiliary relay, a track relay for said track section which is released when said section is occupied, an approach zone of track leading to said switch, a control relay which is energized when said approach zone is vacant and is released when said approach zone is occupied, a first pick-up circuit for said approach locking relay which includes a front contact of said control relay, a second pick-up circuit for said approach locking relay which includes a back contact of said track relay, and a stick circuit for said approach locking relay which includes its own front contact, said first and second pick-up circuits and said stick circuit each including a front contact of said first auxiliary relay and a back contact of said second auxiliary relay.

5. In a railway signaling system, in combination, a signal governing movement of traffic in a track stretch, a signal control relay effective only when energized to establish a circuit to supply energy from a source of energy to the signal to thereby cause the signal to provide an indication, a checking relay having one terminal of its winding connected to one terminal of said source, means effective when the signal control relay is deenergized to connect the other terminal of said checking relay to a portion of the circuits over which energy is supplied to said signal, and means including a back contact of said checking relay for supplying energy to said signal control relay.

EARL M. ALLEN. 

